a) Field of the Invention
The present invention relates to an adjustable book holder.
b) Brief Description of the Prior Art
Book holders are known per se and already form the subject matter of a few patents.
Thus, Canadian patent No. 96538 of E. Power et al. granted on Nov. 23, 1905, describes a book holder for supporting and holding covers of a book while pages thereof are retained in an open position. The book holder comprises a frame for the opened book covers to lay upon and fingers for retaining the covers in position. Also, the book holder comprises bearing brackets extending lengthwise from the frame, rock-shafts carried in the brackets, and presser-feet for retaining the pages of the book in the open position, each one of the presser-feet fixed at one end of the corresponding rock-shaft. Furthermore, the book holder comprises springs to rock the shafts and maintain the presser-feet in pressure contact with the opened pages of the book, and mechanism for simultaneously rocking the rock-shafts against the action of the springs to raise the presser-feet from the pages of the book.
Also known in the art, there are the following patents which describe different adjustable book supporting devices:
Canadian Patent Nos.: 43,089 of J. W. ZAVADIL, granted on Feb. 22, 1893; 87,098 of P. PETTIT, granted on Mar. 2, 1904; 120,520 of A. MORAND, granted on Sep. 26, 1908; 1,244,312 of F. COTE, granted on Nov. 8, 1988; PA1 U.S. Pat. Nos.: 1,392,200 of J. A. NAKONEY, granted on Sep. 27, 1921; 1,590,726 of B. CORSGREN, granted on Jun. 29, 1926; 2,774,177 of J. B. MURGIA, granted on Dec. 18, 1956; 3,076,285 of V. M. SPARKMAN, granted on Feb. 5, 1963; 3,215,482 of B. J. LITKE, granted on Nov. 2, 1965; 3,905,573 of J. M. DAVIS, granted on Sep. 16, 1975; 4,275,863 of D. A. HARTMAN, granted on Jun. 30, 1981; and 4,925,144 of D. E. WHITE, granted on May 15, 1990.
If the known book holders are interesting, they all have the common drawback of not having the necessary means for firmly holding a book in a predetermined position while allowing pages thereof to be easily turned.